Comparative Assessment of Continuous Flow Photocatalytic Oxidation Reactors for Organic Wastewater Degradation

Photocatalysis is an environmentally friendly technique for removing organic pollutants such as dyes, pesticides, etc. The photo reactors could be of the slurry type and fixed bed type. Continuous flow photocatalytic reactors generally are fixed bed-type reactors. Slurry type designs like loop thin-film slurry flat-plate photoreactors, step aeration slurry reactors etc. were also tried out for continuous flow operations. Continuous flow photocatalytic reactors have become one of the most ensuring methods for the treatment of mass water. However, uniform dispersion of the photocatalyst within the wastewater volume is still existing as a challenge. Different reactor designs like immobilized bed reactors (packed bed reactor and fluidized bed reactor), annular reactor with photocatalyst coated on inner/outer cylinder, photocatalytic membrane reactors, tubular reactors, microreactors, etc. are tested for their efficiency. This review tries to provide a generalized comparison of the relative merits and demerits of these reactor designs and immobilization methods on the degradation of organic contaminants.